Assertion Error

Hello- Enjoy the tool so far as it is exactly what I need for a project I am working on.

I have been working on a graph and am repeatedly encountering an error message, noted below. I get this message each time I chose to layout the graph.
If I change the layout type and then chose to "Lay Out" again, it pops up. I ignore it and it will allow me to continue to work (no crash).

Does this happen only with a particular workbook, or does it occur with every new NodeXL workbook you create? Did it occur the first time you tried the program? I'm trying to figure out if there is some particular state your workbook has gotten into that
I never thought of (I'm the NodeXL programmer), or if something went wrong with setting up NodeXL on your machine.